How plants survive droughts

Understanding which species can recover from drought, under what conditions and the mechanistic processes involved, will help researchers predict plant mortality in response to global climate change.

In response to drought, some species die because of embolism-induced hydraulic failure, while others recover, following rehydration. Several tree species have even evolved strategies to avoid embolism, while others tolerate high embolism rates and recover their hydraulic functioning upon drought relief.

This research focuses on structures and processes that might allow some plants to recover from drought stress via embolism reversal.

The researchers explore how embolism repair may have evolved and the anatomical and physiological features that facilitate this process looking at possible trade-offs and related costs to plant growth. Recent controversies on methods used for estimating embolism formation/repair are also discussed, providing some methodological suggestions.

Although controversial, embolism repair processes are apparently based on the activity of phloem and ray/axial parenchyma. The mechanism is energetically demanding, and the costs to plants include metabolism and transport of soluble sugars, water and inorganic ions.

The researchers propose that embolism repair should be considered as a possible component of a ‘hydraulic efficiency-safety’ spectrum. They also advance a framework for vegetation models, describing how vulnerability curves may change in hydrodynamic model formulations for plants that recover from embolism.